1. Field of the Invention
The present invention relates to transporting wind turbine blades. More specifically, the present invention relates to a system and method for transporting long airfoils via railroad using a sliding support assembly and plural railcars.
2. Description of the Related Art
Large-scale wind turbines are used to generate electrical power. Such wind turbines consist of a tall tower with a generator nacelle rotatably coupled about the top of tower's vertical axis. A rotor hub extends out a horizontal axis of the nacelle. Two or more turbine blades are connected to the rotor hub at right angles to the horizontal axis. During operation, prevailing winds cause the turbine blades to rotate about the rotor hub's horizontal axis. The rotational forces are coupled to a generator within the nacelle, which produces electricity. The nacelle rotates about the vertical axis of the tower to maintain the wind turbine blades in proper orientation with the direction of the prevailing winds.
The various components of a large-scale wind turbine may be manufactured at different geographic locations, which may be anywhere in the world. For example, a manufacturer who wishes to assemble a wind turbine generator tower in the United States may have the towers manufactured in Korea, the nacelles manufactured in Denmark and the blades manufactured in Germany. These components must then be then transported to the ultimate power generation site, assembled, erected, and placed into operation. Since the manufacturing operations may be spread across the world, transportation of the components to the generation site may utilize all modes of transportation, including ships, barges, trains and trucks. The various components are expensive to manufacture, and include delicate components that must be protected and handled properly during transportation. The transportation issues are exacerbated in that the components may be transported using plural modes during their journey. For example, a wind turbine blade manufactured in Europe may travel by ship across the ocean, then via railroad to a location in the geographic area of the generation site, and then finally by truck to the ultimate destination.
The evolution of technology and the economies of scale have lead to the development and deployment of large-scale wind turbines with larger and larger proportions. The power generation capacity of a large-scale wind turbine is directly related to the length of the turbine blades, which define the swept area and power capacity of the turbine. The wind loading stresses involved during operation, and the need to keep the total mass of the turbine blades reasonably low, has lead engineers to design and build turbine blades as monocoque structures, typically employing composite materials. The lengths of these structures have grown to over 100 feet in length and at present approach 150 feet in length. Transportation of long turbine blades presents significant challenges to transportation engineers, particularly in the case of railroads, where the railroad profile is tightly limited and the trains must traverse curved sections and complex rail yards. Thus it can be appreciated that there is a need in the art for a system and method addressing the problems related to transportation of long wind turbine blades and other long airfoils via rail.